Secondary battery and battery module, battery pack and apparatus comprising the secondary battery

A secondary battery, comprising a housing as well as an electrode assembly and an electrolyte contained in the housing, the electrode assembly comprising a positive electrode plate, a negative electrode plate and a separator, and the positive electrode plate comprising a positive current collector and a positive electrode film that is disposed on at least one surface of the positive electrode current collector and comprises a positive electrode active material, and the negative electrode plate comprising a negative electrode current collector and a negative electrode film that is disposed on at least one surface of the negative electrode current collector, wherein the positive electrode active material comprises one or more of lithium nickel cobalt manganese oxide and lithium nickel cobalt aluminum oxide;

• the negative electrode active material comprises silicon-based material and carbon material;
• and the secondary battery satisfies:
• 0.05≤Z≤0.6,
• wherein
• Z={Vt−V0−(Hb−Ha)*S−V1}/CAP;
• Vt represents a volume of internal space of the housing, in cm3;
• V0 represents a volume of the electrode assembly when the battery is at 0% SOC, in cm3;
• Ha represents a thickness of the negative electrode film when the battery is at 0% SOC, in cm;
• Hb represents a thickness of the negative electrode film when the battery is at 100% SOC, in cm;
• S represents total area of the negative electrode film in the battery, in cm2;
• V1 represents the volume of the electrolyte in the battery after formation, in cm3;
• and
• CAP represents a rated capacity of the battery, in Ah.